There are two versions of each of those functions, and the other version does take a byte[] for a parameter. I really don't get what a single byte would do either, since it's not usable as an out parameter. And the Android documentation for GLES is just nonexistent from what I can tell.

java-gaming.org is not responsible for the content posted by its members, including references to external websites,
and other references that may or may not have a relation with our primarily
gaming and game production oriented community.
inquiries and complaints can be sent via email to the info‑account of the
company managing the website of java‑gaming.org